Damage Performance Of CSPRP Under Cyclic Loading

Reinforced concrete structures will occur to irreversible damage under cyclic loading,which behave macroscopically in the development of cracks,the reduction of stiffness and so forth.Aimed at accurately describing the damage,numerous damage models have been proposed based on a number of structural tests,seismic damage investigations and structural failure criteria.These damage models are based on displacement,stiffness,energy consumption or other indicators.However,the complexity of the damage development of reinforced concrete structures makes partial damage models complicated in form and difficult in calculation,and these damage models cannot accurately described the damage of reinforced concrete structures.General problems of these damage models are that when the structure works in the elastic range,the damage index D is much larger than 0 and that when the structure is close to collapse,the damage index D does not converge to 1.In order to solve above problems,based on the quasi-static test results of concrete composite slabs with precast ribbed panels(CSPRP),the effects of energy dissipation and residual displacement on the damage of CSPRP were analyzed in this paper.It is found that setting side beams on the outside of the panels,increasing the amount of bending reinforcement and transverse reinforcement can reduce the residual displacement while adding anti-cracking steel bars cannot effectively reduce the residual displacement.Subsequently,the feasibility of using single energy indicator to evaluate the damage was demonstrated,and the evolution of energy in the quasi-static test of CSPRP was analyzed.The results shows that the cumulative energy consumption of first-passage and fatigue can be used to separate the effects of the first-passage damage and fatigue damage respectively.Then,the energy-based damage model was established and the damage of CSPRP was analyzed.The calculation resultes show that the energy-based damage model has specific physical meanings and good upper and lower bounds convergence abilities.For seismic performance-based design of structures,performance levels of normal operation,reparability and prevention of collapse of the components were determined.Afterwards,due to the small application range of the established energy damage model,this paper changes the normalization method of displacement term and energy term of Kumar damage model,and established displacement-energy damage model.A total of 30 reinforced concrete members including panels,walls,beams and columns were used to examine the applicability of the model and determine the performance levels of the components.The result shows that the damage value of the proposed displacement and energy-based damage model is less discrete and the assessment for damage performance is more stable than the other models.Finally,in order to calculate the damage of CSPRP after an earthquake,the residual displacement-based damage model were established and the performance levels of the components were determined based on the displacement and energy-based damage model proposed in this paper.In order to determine the relationship between the ultimate displacement in the damage model and the reinforcement of specimens,influences of different factors on the ultimate displacement of CSPRP were analyzed and the calculation formula of the ultimate displacement was given.Results show that longitudinal reinforcement ratio,transverse reinforcement ratio,and bending reinforcement ratio have great influences on the ultimate displacement of CSPRP.